Classical Indian astronomy documented in literature spanning the Maurya (Vedanga Jyotisha, ca. 5th century BCE) to the Mughal (such as the 16th century Kerala school) periods.

The first named authors writing treatises on astronomy emerge from the 5th century CE, the date when the classical period of Indian astronomy can be said to begin. Besides the theories of Aryabhata in the Aryabhatiya and the lost Arya-siddhānta, we find the Pancha-Siddhāntika of Varahamihira. From this time on, we find a predominance of geocentric models, and possibly heliocentric models, in Indian astronomy, in contrast to the “Merucentric” astronomy of Puranic, Jaina and Buddhist traditions whose actual mathematics has been largely lost and only fabulous accounts remain.[citation needed]

The astronomy and the astrology of ancient India (Jyotisha) is based upon sidereal calculations, although a tropical system was also used in a few cases. For example, Uttarayana (Uttarāyana उत्तरायण) was determined according to a tropical system in the Mahabharata, or by Lagadha in the Vedanga Jyotisha. But even then, sidereal astronomy was the mainstay. Now, even Uttarāyana is determined according to the sidereal system of Hindus.